Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
cam thuc » am thuc, nam thuc, cam thu
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
ty nang » ky nang, ty xang, ty hang
sach ty » sach y, sach tu, sach thu
danh di » xanh di, danh dien, danh gia
danh du » danh dau, danh tu, dinh du
hanh de » hanh ve, hanh kem
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ty nang xa hoi. hieu va cam thuc vat ((((danh di) OR (danh du))) or (hanh de)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang xa hoi. hieu va cam thuc vat ((((danh di) OR (danh du))) OR (hanh de)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty nang xa hoi. hieu va cam thuc vat ((((danh di) OR (danh du))) or (hanh de)) cua tre".
• Adding a wildcard symbol may retrieve word variants: doc sach ty nang xa hoi. hieu va cam thuc vat ((((danh di) OR (danh du))) or (hanh de)) cua tre*.